c++ - Capture theme-related items on window -

i working on application have capture screenshot of window window of application invisible (hiding it, making screenshot, showing again not option due number of reasons). walking on top-level windows, building z-order, , capturing necessary area of them bitmap 1 one. in general works, except things x, minimize, , maximize buttons on top-right of window bar not show up, black box. assuming because drawn windows without use of gdi, not on dc of window, , can't bitblt() them.

is there can it? except dirty tricks of course.

i suspect use 32bit bitmap (with alpha channel) render whole thing.

gdi not support alpha in general and, worse, different gdi functions deal alpha byte inconsistently.

try use 24bpp dib destination bitmap avoid inconsistencies.